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There's been a lot of talk recently about Vin Naturel. There have been several Natural Wine Fairs around France and in the UK too, which have thrust these products under the spotlight. But why call your wine "naturel" when you can go down the Organic or Biodynamic route?

The two stand-out issues with Natural Wine are that no yeasts can be added during the fermentation process, and no sulphur, in whatever form, can be used either in the vineyard or in the winery.

By not adding any yeasts to the mix, the winemaker is relying upon the naturally occurring yeasts which are present on the skins of the grapes, and in the air, to do the job of fermenting the juice. It sounds very logical, but sometimes this can lead to the fermentation process being slow to kick in, or not finishing properly, leaving higher levels of residual sugar, and a bit of fizz. A visitor to a recent Natural Wine Fair told me that many of the wines were still fizzy and over-sweet, due to unfinished fermentations. There is therefore a risk in producing Natural Wine.

The risk is further enhanced by the absence of sulphur in all stages of the process. For the vast majority of vignerons, sulphur is absolutely indispensable. In the vineyard it is sprayed as a dry dust, or mixed with water, to protect the vine against oïdium. The sulphur reacts with microbes on the vine leaves to create sulphur dioxide (SO2) which lowers the pH level, and stops the oïdium fungus from propagating.

As soon as the grapes are harvested, sulphur, or more precisely, Sulphur Dioxide has many roles. The grapes and juice may have SO2 added to sterilize them, but mainly to prevent oxidation. At the start of the fermentation process, it may be added to kill naturally occurring yeasts which could kick-start the fermentation before the commercial yeasts have had a chance to work. At bottling time, SO2 can be added, particularly to whites, rosés and sweet wines, to sterilize and prevent against oxidation. So how is it possible to make wine without using commercial yeasts and in particular, sulphur?

Experienced natural wine makers will tell you that there is enough yeast naturally occuring for the fermentation. Sometimes, a little patience is needed. They will also tell you that there is enough sulphur naturally present in the soil to supply the vine with all it needs. In the fermentation process, sulphur is a minor by-product, so again, provides some protection to help the wine through the vinification process. Needless to say, natural wine is not currently a massive industry, although there are clearly more and more vignerons taking to it. There are undoubtedly those who believe it's an easier way to get into a niche market than going down the Organic and Biodynamic routes, which can take years.

As a footnote, it is worth mentioning that Organic and Biodynamic producers are allowed to use a certain amount of SO2. Less than the EU limits, but consequential even so.

So what's the big deal with sulphur or more precisely sulphites? It is implicated in many of the day after headaches, particularly those associated with whites and rosés, and there are many people who have allergies to certain sulphites, which can cause various reactions, including asthma attacks. Other, longer-term effects haven't been officially proven so far although there are plenty of theories.

There's no doubt that a good Natural Wine, that has finished its' fermentations, and has had no sulphur added, has got to be a healthier product than the mass-produced, chemistry-set wines that form the bulk of the commercial offering. So whilst I'm still skeptical about some vignerons jumping on the Natural Wine bandwagon, it can only help to draw our attention to the fact that our wines are sometimes choc-full of chemical compounds,

For the next Newsletter, we will taste some of the local Natural Wines and report back to you.

Dominic George. Copyright 2011

17th June 2011

I was recently asked to do some translating at a local wine event. I agreed, without asking any further questions, as I just expected to be translating a few general speeches, and then to tuck into the dinner. However, one of the speeches was by a brilliant researcher from Montpellier University, whose speciality is the chemistry of wine aromas. My French is good, but translating this stuff was pretty much beyond me. However, despite the obvious complexity of the subject, it encouraged me to do a bit of research and try and come up with a basic introduction to a fantastically complicated area of research.

So, what exactly is an aroma? An aroma or more correctly an aroma compound is a volatile chemical compound. Volatile because it has the capacity to vaporize and therefore reach up the nasal cavity to the olfactory bulb, where, if it has a detectable odour, it can be smelled. However, as we shall see, the molecules that are present in these compounds also play a role in determining the taste of the wine as well.

When we taste wine, the aromas that are present can in theory be classed as Primary, Secondary and Tertiary aromas. The Primary Aroma is the initial impression of the wine just after it has been poured. If the wine is good, ie: not corked or off or over-sulphured, then we should decern the aromas which are typical to that grape variety, and of which, molecules are present in the skin and pulp of the grape. For example, researchers have discovered that a molecule called 2 méthoxy-3 isobutyl-pyrazineis responsible for the aromas of green peppers in Cabernet Sauvignon and especially Cabernet Franc wines. The depth of the aroma depends upon many things: climate, soil, sunlight and crucially the level of maturity of the grape. Also, if as is often the case, the wine is blended with other grape varieties, it can enhance, or more often, lessen the impact. So we can say that these primary aromas are part of the DNA of each particular grape variety. Perhaps the most famous Primary Aroma is the Lychee aroma associated with the Gewurztraminer grape.

The secondary aromas are those which will start to become decernable after around 10 minutes, when the wine has been opened and in particular swirled around a glass. These aromas are produced during the fermentation processes (alcoholic, malolactic and also carbonic maceration), when the action of the yeasts on the sugar produces alcohol and CO2. Alongside these reactions, there are many secondary reactions which affect the aroma molecules, mainly due to certain enzymes in the developing wine. Researchers now know that some of these secondary aromas are always potentially present in differing grape varieties, but need the fermentation process to release them. The intensity of these aromas varies according to the fermentation conditions: temperature; amount of sugar and yeasts present. In theory, the more sugar present, the more active fermentation there is, and therefore more secondary reactions which will promote certain aromas. For example, sweeter wines such as those made from Muscat grapes , have very pronounced Secondary Aromas. We often talk about peach and apricot aromas in Muscat, and these are the result of the fermentation process.

Tertiary aromas are a slightly easier area to define, although still full of complicated detail. These are aromas which become prevalent during the ageing process ie: they are down to the barrel or vat or bottle. For example, an oaky smell would obviously indicate barrel-ageing. Notes of vanilla are also associated with barrel ageing, and are more or less prevalent depending upon the provenance of the barrel and the grape variety. Syrah raised in new American oak barrels is often perceived as having very strong vanilla aromas.

As you can see, this is a complicated subject, and I have barely scratched the surface. However, it shows what a fascinating area of research wine aromas are. It also suggests that as research advances, and certain molecules and enzymes responsible for the production of particular aromas are identified, then it can't be too long before wines will be manipulated to produce exaggerated aromas. Or perhaps it's already happening.......................

Dominic George. Copyright 2011